The Benefits and Tradeoffs of Social Distancing

By Kevin Dennehy

Long before the COVID-19 crisis, Eli Fenichel, an economist at the Yale School of Forestry & Environmental Studies, studied the effectiveness of — and the tradeoffs associated with — social distancing. In fact, when he first interviewed for an appointment at the school, his presentation was on research that showed that people would likely change their behavior enough during an epidemic to reduce the number of cases.

This week we spoke with Fenichel about what his past research revealed, how it is applicable to the current global crisis, and how this pandemic might strengthen future research and responses to other global threats, including climate change and biodiversity loss.

You’ve been looking at issues related to social distancing for many years. What have you learned about social distancing as an intervention strategy?

Eli Fenichel: It’s a complicated answer. We know that social distancing works if the goal is to reduce cases. If we all locked ourselves in a closet and had no human contact for three or four weeks, this would go away. However, lots of people would probably die in those closets from other causes besides COVID-19. What I've been looking at for a long time is how much do we need a government to tell us to lock ourselves up, and how much would people do it on their own.

Eli Fenichel, Knobloch Family Chair of Natural Resource Economics

We want people to social distance right now, it’s extremely important. But we want people to do it strategically and, ideally, voluntarily because if they’re doing it voluntarily, they're probably doing it at least cost. The challenge that we're facing right now is there's been a lot of discussion in the media in recent days about the balance between killing people or killing the economy, and that’s the wrong way to look at it. What we really need to worry about is how do we manage this so we minimize total mortality. Putting aside economic concerns for a moment, we want to make sure that our response to COVID-19 isn’t causing more non-COVID-19-related deaths. There’s a mortality/mortality trade-off here... More people are going to die this year; there’s no way out of that. The question is how do we manage that, how do we manage those trade-offs, and how do we manage future premature mortality?

You raised the question of the role of government. What should the government response be when the rate of contagion is so high, and people aren’t voluntarily distancing?

Fenichel: The Number 1 thing the government needs to do is provide clear, accurate information. The next thing that the government needs to do is coordinate things that the private industry might not be very good at doing. That includes testing. The other thing is getting the incentives right for people to social distance. I mean, I think the most important thing the government has done on that front so far is offering paid sick-leave.

In our research, we looked at models of whether people will social distance. We found that people who are susceptible to pathogens tend to do some social distancing because there’s a private benefit to not getting sick. No one wants to get sick, especially with a pathogen that has a high mortality rate. The problem is, once someone gets infected — and becomes infectious — there have no incentive to social distance. It’s like, “I’m already infected. But, if I don’t feel so bad, why bother?” Especially if the trade-off is not paying the rent or not buying medicine or something else. That's a huge problem.

What do your models show in terms of how social distancing might most effectively curtail or reduce the impacts of an epidemic?

Fenichel: There’s only three ways out of an epidemic. One that I call “the miracle,” in which summer comes and somehow this disappears. Unfortunately, that means it’ll just come back with a vengeance in the fall.

But, it’ll buy us some time. It’s not very likely. Another is what we call “stochastic die-out.” That could occur if you got people to isolate just enough to see a significant decrease in the number of cases. Then, those people who are infectious don’t come into contact with people, and the thing dies out. But, we have way too many cases to hope for that anytime soon.

The only other way out of an epidemic is to exhaust the susceptible population. And, there are two ways of doing that. You get a lot of people sick, and they acquire immunity through being sick, or you get a vaccine.

One of the projects you published in the past couple of weeks is an online dashboard [produced with the Yale Child Study Center and the Zigler Center in Child Development and Social Policy] which illustrates childcare needs for those people working in key sectors responding to this pandemic. How did that come together?

Fenichel: Well, Jude Bayham [a former F&ES postdoc who is now an assistant professor at Colorado State University] and I have been working on a paper for a long time looking what happens to children during epidemic-related school closures. We finished it four or five years ago but couldn't get anyone to pay attention to it because they thought what we were talking about was absurd. So, we’ve continued to try and refine it and make it more appealing to economists as, at least, an interesting thought experiment. In that paper, there was a footnote about the childcare demand for healthcare workers. When this happened, we decided to revisit that question.

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And, while there’s obviously a lot of focus on healthcare workers, there are many other people considered essential workers who are affected by school closures — janitors who are cleaning those hospitals, the people stocking the shelves at your grocery store, the people who are making hand soap and putting it on trucks and getting it around the country right now, and the others who are keeping things going. We published that last week.

This week an expanded version of that team, published a risk assessment by industry for the entire U.S. This can help highlight counties that might have particularly vulnerable workforces in critical industries, such as nursing homes or grocery stores. It also helps policy makers get a handle on the lost wages for those likely to get seriously ill from COVID-19.

What does this pandemic tell us about other environmental threats facing the planet?

Fenichel: One of the things I think is really important for us to remember — and for our School community to keep in focus — is that this is basically just climate change at warp speed. And, it's biodiversity loss at warp speed. It’s every one of these sort of social-environmental dilemmas, because this is an environmental-social dilemma. We basically have a predator trying to kill us, right? It’s not malicious. It’s just that’s what predators do. And we have just gone from being a predator to prey, and we’ve got to figure out how to live in that world.

All of the tools that we at F&ES and other environmental studies school are extremely relevant right now. We just need to figure out how to shift from something that was rolling out over years and decades to something that is changing daily.

Are you optimistic that people going through such a traumatic moment — which is so relevant to their lives — will have increased awareness of the importance of science, of expertise, of good data analysis?

Fenichel: This is where systems thinking and the kinds of interdisciplinary thinking we do at F&ES is so important. I hope that what we’ve done so far illustrates the importance of the F&ES Environmental Data Science Initiative. But we’re going to need to continuing looking at these issues more broadly. We are going to run up huge national debts, which will have major consequences. After this is over and the economic recovery begins we’re going to have factories running full-bore, so there will be enormous environmental damage costs.

We, in the F&ES and broader environmental community, all need to roll up our sleeves and do what we can. We know how to work with data and how to solve big, complicated systems problems. Let’s do it.

When I first interviewed at F&ES many years ago, I presented a paper on social distancing during an epidemic. And, I was hired because the faculty recognized that what I was talking about was not fundamentally different from the sorts of problems we deal with at F&ES and in the environmental sphere. So, if we actually use this as a learning moment rather than a moment to panic, maybe we can come out of this stronger.